Fix VideoWriter silent initialization failures causing abrupt recording stops

[Copilot]

VideoWriter could silently fail during initialization (invalid codec, disk space, permissions) but continue execution, causing recordings to appear started while actually stopped immediately.

Changes

Core Fix (node_video_writer.py)

• Added isOpened() validation after cv2.VideoWriter creation
• Wrapped legacy mode initialization in try-except with crash logging
• Early return on failure preserves "Start" button state for retry
• Progress bar displays specific error messages

Before:

self._video_writer_dict[tag_node_name] = cv2.VideoWriter(...)
# Continues silently if VideoWriter failed to open

After:

video_writer = cv2.VideoWriter(...)
if not video_writer.isOpened():
    create_crash_log("recording_start_videowriter_failed", RuntimeError(...))
    dpg.configure_item(progress_bar, overlay="Error: Failed to start")
    return  # Button stays "Start" for retry

Testing (test_videowriter_initialization_validation.py)

• 7 test cases: invalid codec, path, FPS, dimensions, success case, error flow
• Platform-independent test constants

Error Scenarios Now Handled:

• Unavailable codecs (MJPEG, H.264, FFV1)
• Insufficient disk space
• Permission denied on output directory
• Invalid video parameters (zero FPS, zero dimensions)

Impact

Users now receive immediate feedback on initialization failures with crash logs containing diagnostic information. No breaking changes—only adds validation layer.

Original prompt

pourquoi quand je clique sur start (le record), sur le noeud videowriter, ça peut s"arréter brutalement ? corrige stp

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.